This invention relates to a tremolo system for stringed instruments.
Many modern day guitars are equipped with devices and mechanisms which enable the tension in the strings to be dynamically altered whereby the pitch or tone of the sound produced by the strings can be varied.
Conventional tremolo devices incorporate a pivotal lever which is usually located on the front of the guitar body adjacent to the high `E` string, the performer first of all playing a note or cord and then moving the tremolo lever to alter the tension in the relevant string and to obtain the desired effect.
Perhaps the most notable and successful tremolo devices are those of Fender Musical Instruments Corporation and D Floyd Rose introduced in the 1950s and the 1970s respectively.
The Fender device involves what is now considered as relatively conventional or traditional machining of the guitar to provide a slot in the upper surface of the guitar body, and an L-shaped volume within the guitar body below said slot. The tremolo lever is integral with a base plate or bridge assembly to which one end of each guitar string is attached, one edge of the base plate being screwed to the guitar body to be pivotal about said screws on movement of the lever against the bias of springs located within said volume in the guitar body and reacting between the guitar body and an extent of the base plate assembly projecting downwardly into said volume.
Such an arrangement, in which the base plate assembly moves with the tremolo lever, is acknowledged as providing excellent `feel` to the performer and good sound quality, but suffers from certain disadvantages. In particular there is limited movement available to the tremolo lever in a direction tensioning the strings before the base plate of the assembly interferes with the surface of the guitar body, while pivoting movement of the lever and the consequential movement of the base plate assembly causes the strings themselves to be raised and lowered relative to the guitar body. This can result in contact of the strings with the fingerboard and/or undesirable alteration in the fine tuning of the strings.
Instead of pivoting the base plate about screws, the Floyd Rose device incorporates fixed pivots screwed to the guitar body, the movable base plate to which the tremolo lever is attached being provided with a knife edge which seats on said pivots to pivot thereabout on movement of the lever against a spring arrangement similar to that of Fender.
The Floyd Rose device suffers from some of the disadvantages associated with Fender, although the upper surface of the guitar body is shaped to enable pivoting of the base plate in both directions. However this requires additional machining of otherwise conventional guitar bodies.
A further known tremolo system by Kahler departs from the pivotal base plate arrangement and provides an integral block adapted to be located into a suitably machined recess in the body of the guitar. This system embodies a base plate fixed to the body of the guitar and a bearing arrangement mounted in the block above the surface of the guitar body about which the tremolo lever is pivotal against the bias of springs contained within the block.
Although there is less undesirable movement of the strings than in the aforementioned systems, the Kahler arrangement requires the provision of special purpose springs and a roller to keep the system in equilibrium, and involves a large amount of machining to the instrument body prior to installation. Furthermore, the sound produced by the Kahler system is generally inferior to that of Fender or Floyd Rose systems, there being no direct resilient connection between the lever and the body of the instrument as is provided by the balancing springs in the latter systems.